The small size and high density of today's electrical apparatuses has created a demand for extremely thin electric wires. When wire is cut in a predetermined length for use as a part in an apparatus, automatic inspection of the length is very difficult because the cut wires are thin and irregularly curved. It is not easy to stretch a curved thin object along a scale. Further, it is difficult to stretch a line-type object without adding load and thus distorting the length measurement. Inspection of the length must therefore be performed manually. Unfortunately, the shortage of skilled manual laborers has made it difficult to inspect flexible thin objects such as thin pieces of wire.